The present invention relates to a predictive scanning input system for rapid selection of visual indicators corresponding to keys on the keyboard, each key corresponding to one of a plurality of symbols. The predictive scanning relates to an input system to be utilized to input information to later be synthesized to produce audible or recorded data. In one preferred embodiment, the system relates to an input system for a linguistic coding system for use by people unable to use their own voices to create either a synthesized speech or synthetic printed messages. The input system is directed toward a system upon which, upon activation of a first key, a plurality of visual indicators are activated on certain of the remaining keys when they are found to correspond to a plurality of symbol sequences which may be formed utilizing the initial input symbol of the activated first key. Thus, it thereby defines a limited number of keys which can produce a stored message involving that initial input key. Therefore, the input message can then be utilized to create synthetic speech or be output to a printing device, with the processed information being based on a sentence or message rather than a word, phoneme or letter.
Previously, a system and method for producing synthetic plural word messages was developed by Bruce Baker et al and is disclosed in U.S. Pat. No. 4,661,916 to Baker et al and issued on Apr. 28, 1987, the disclosure of which is incorporated herein by reference. The system is directed to a linguistic coding system and keyboard for the use of people unable to use their own voices. The coding system and associated keyboard are based on sentences rather than a word, phoneme or letter.
In such a system, the keyboard is coupled to a computer which stores a plurality of plural word messages or sentences in the memory thereof for selective retrieval by the keyboard. The sentences retrieved from the keyboard are fed to a voice synthesizer which converts them through a loudspeaker to produce audible spoken messages. The keyboard utilizes polysemic (many-meaning) symbols, also known as icons, corresponding to respective keys. By designating selected ones of the keys and their associated symbols, selected recorded plural messages may be accessed from the memory.
With the system described in U.S. Pat. No. 4,661,916, however, plural messages in the memory could be retrieved from memory by actuating a combination of designated primary message theme keys and other keys to vary the context of the polysemic symbols. Thus, a plurality of sentences could be selectively generated as a function of polysemic symbols in combination with other symbols. However, if a scanning system is utilized to activate the plurality of keys on the keyboard, it can take an extremely long amount of time to activate each of the switches corresponding to a sequence of symbols needed to access a particular message.
Row-column scanning system have previously been developed to sequentially access rows and columns of a keyboard. In row-column scanning, each row lights up in succession. When the row is illuminated which contains the key which a user desires to select, a switch is hit. After the user has hit the switch, then each key in succession from left to right in that row lights up. When a desired key is illuminated, the switch is hit again. Thus, each key selection requires two actuations. The first actuation determines the row and the second actuation determines the column. Row-column scanning is usually very slow. The more keys a user must scan through, the longer it takes.